the case centers on the conviction of steven mcfadden for selling bath salts designed to mimic the effects of chemically similar narcotics. the case heard oral argument mcfadden versus united states in april. this is an hour. >>> we will hear argument this this morning in case 14378 mcfadden versus united states. mr. russell. >> mr. chief justice, may it please the court. the briefing in this court has narrowed considerable the disagreement among the parties. we now all agree that the fourth circuit ms. con struns the men's real for a criminal offense upped the controlled substances analogue act. we further agree that the jury instructions begin in this case were ear these. instead, we government now agree that to prove an offense the government must show that the government knowingly distributed an a log. which showing noeg that the substance in question had the characteristics of making it an analog under the statue tut. over the government's alternative theory that it can show that the defendant knew that the substance was illegal or regulated. if all the government means by that is ill